VM can't solve 6-minute packet loss

I couldn't take FTTC's sluggish 68Mbit speeds anymore, so I've recently subbed back to VMB on their 1Gig offering and received my Hitron CHITA in December, however I'm experiencing a persistent connectivity issue that 5 engineers have been unable to diagnose and am at the end of my tether now, hoping to share my experience and perhaps someone else is going through the same can sympathise or offer a possible solution/advice on what else can be done.

I noticed in mid-early January that all my video calls (Zoom, Google Meet, FaceTime) have the video & audio freezing every few minutes. Ran some tests - about every 5 minutes there is packet loss.
Here is what it looks like, visually

I started monitoring at the end of January using various methods (TBB ping tool, PingPlotter). Every 6 minutes there is a packet loss.
On a few occassions it stopped and went back to normal (2 long intervals and a few much shorter ones). Outside of these times it's always dropping packets every 6 minutes:
25th Jan 21:00 - 2nd Feb 19:00
7th Feb at 18:41 until 12th Feb 15:58
13th Feb 04:17-11:40
17th Feb
8th March: 08:02-14th March 11:00

In late Feb the engineer came around, swapped the modem but after demonstrating to them that the issue still persists, he said he will delegate it to the network team, then after waiting around for days there was a week-long spell in early March when I thought it was fixed (though they never informed me of what was going on and I am too busy to constantly check up on them). Unfortunately it wasn't fixed and the packet loss has re-surfaced with a vengeance.
A few weeks ago I got very fed up and started calling their support line saying problem isn't fixed and they wanted to take me through 'reset your modem' stuff again, I said no thanks, we've done that and it doesn't help, next steps please! Engineer comes around, can't fix it. 'Network' says I must have a dedicated cable and they will run some tests on their end to rule out their own equipment.

They send out a team to run a new cable (because up to now it was 1 cable running indoors for a few other apartments to share, and there's some internal wiring involved).

Issue is still unresolved, so another team comes around and this time re-runs the cable and drills my wall (which we have thus far avoided as the building had some pre-existing internal coax cable that has served fine).
Issue is still unresolved. The last team who ran the new cable was boggled as to why this is happening and seemed keen on resolving it and promised to revert to me on Friday, but didn't.

My setup: Hitron Chita < > own enterprise router, so the CHITA has gateway function disabled and it is in bridge mode. During initial testing, I have tested it by factory resetting and connecting just one PC to the hub and nothing else, but the issue persists. I have re-run the test again over the last day and it most certainly drops packets every 6 minutes or so.
Therefore, I've ruled out my own equipment, they ran a new cable and it's still happening.

What else could it be? Is there anything else I can do in the situation? Is it their modem or street cabinet that's defective?

Thanks in advance!

For anyone else experiencing such packet loss with a DOCSIS 3.1 / 1Gig plan, today at 1am the issue seemingly disappeared, again.
My VM contact disappeared last week and hasn't contacted me, so I have no idea if this is accidental or if they could have really fixed it for real.
Suppose it depends on how long the issue will remain 'fixed' now.

Turning a bit into a blog, this!

VMB Have promised to revert within 12-hours as per their SLA and it's been nearly 48 hours, they must have given up.
There was a 4 day period last week where it was 'back to normal' but then the packet loss came back again

Have you tried turning off everything in the premises and checking?

There is an overlap of frequencies which are quite broad based on virginmedia hence the requirement to use their cables and an isolator.

The timing of it feels more to me that something is kicking off every 6 mins it could be a set top box checking EPG updates with a faulty power brick for example. Not even necessarily on your line there is REIN introduced over powerlines.

Do you have an AM radio? Can you tune it to 612? Is there a lot of audible noise? Start with power bricks close to the cable route. Is a tv giving off a bunch of REIN?

Is the route in the building passing a furnace, an HVAC, a ventilation MVAR system, a laundry room, a kitchen, do the wires run close to electrical wires or other cabling that could be interfering? Is there a DAS for mobile service as mobile frequencies overlap with Virgin too?

https://youtu.be/W5pWaeLJW88

I've done a few things.
Asked another neighbour to run tests, and they don't experience this issue.
Connected the Chita directly to another power socket, switched off all other surge protectors with all the other tech.
No set top boxes.

The route of the VM cable is now directly from the outside and there's no internal coax wiring to contend with.

Will have to try and find if there's an AM radio available...

Mini update:

I've went around and switched off practically all power sockets and/or fuses to rule out internal wiring, nothing stopped the issue from happening.

Contacted VMB two weeks ago, they promised a 12-hour turn around time but nobody called.
Contacted them again yesterday, TWICE. The second time they said their 'level 2 team is on it and will contact you very soon' of course nobody contacted me and the pervasive issue persists.

What a nightmare!

A few weeks ago one of the main engineers has come back, explained they've done everything they can and don't know why this problem is happening, and they provided me with a "Hub 3.0" which is DOCSIS 3.0, to test the connection, 390Mbit down/37Mbit up connection.

No more drops every 6 minutes any more. There have been a few drop outs every day, and the connection behaves very differently when it's maxed out, but it's nowhere near as bad as before on the DOCSIS 3.1 Chita modem.

Their solution is to find an old DOCSIS 3.0 hub and downgrade the service tier, since they don't know what's causing it.
Quite bizarre, but they have tried everything from what I can tell but seems like it's their network that's not configured to operate with DOCSIS 3.1 gear or something.

Not sure what to do since I won't ever know if it's safe to upgrade to gigabit if nobody knows the cause of this issue!

I had the same issues and they let me leave to BT - I had VM for years, and the only issue was when I went to 1gb. 2 engineers were clueless

In my case, about 5 engineers including one 'network guy' who never really showed.

Sadly it's the choice between VM or 70Mbit FTTC, no FTTP available yet, so might have to just downgrade or move. If there was FTTP I would of course switch!

I've tried to get some people's attention on Twitter, perhaps other Hitron Chita users can come forward but no success so far.

I may go back to Virgin when the XGS-PON products start they've put the new pillar cabinet outside my house. I'm done with DOCSIS

Edited by BuckleZ (Sun 11-Jun-23 16:19:10)